CN110556606B - Battery pack internal injection emergency cooling control structure and method - Google Patents

Abstract

The invention provides an internal injection emergency cooling control structure and method of a battery pack, and relates to the field of battery thermal management. The structure includes an automobile control unit, an automobile refrigeration system, a controllable valve, a hot melt nozzle, a flame retardant storage tank, a power battery module, a refrigerant manifold, a first pressure relief exhaust valve, a battery pack shell, a second Pressure relief exhaust valve. Through the induction of the hot melt in the hot melt nozzle to the overheated battery module, a signal is transmitted to the vehicle control unit, emergency cooling is started, the controllable valve is opened, and the higher pressure refrigerant is used to entrain the flame retardant through the hot melt nozzle to the The overheated battery module is sprayed. On the one hand, the refrigerant vaporizes and absorbs heat. On the other hand, the flame retardant inhibits combustion. Then, the high-pressure airflow in the package is discharged through the pressure relief exhaust valve. The invention effectively inhibits the overheated battery module from developing in the direction of thermal runaway and greatly improves the safety of electric vehicles.

Description

A battery pack internal injection emergency cooling control structure and method

Technical field

The invention relates to a battery thermal management system and thermal safety application technology.

Background technique

As the energy and environmental crises continue to worsen, people are looking for solutions to these problems. As the main force consuming energy and creating pollution, the automobile industry is in urgent need of adjusting energy consumption and utilization. Electric vehicles comply with the development concept of energy conservation and emission reduction and have developed vigorously. However, there are still many problems. Among them, the thermal management and thermal safety of batteries have always been a matter of great concern. In recent years, electric vehicles have suffered from battery thermal runaway problems. Explosions and spontaneous combustion accidents occur frequently.

In order to deal with the overheating problem of the battery, people have proposed a variety of mainstream cooling methods such as air cooling and liquid cooling. However, as the energy density of the battery continues to increase, its heat production rate continues to increase. Although the traditional cooling method is within the normal temperature range of the battery, It has excellent effects, but it is no longer capable of working when the battery temperature is in the overheating range. Especially under certain extreme working conditions, it is easy to cause thermal runaway of the battery, which may damage the battery pack in mild cases or cause combustion and explosion accidents in severe cases. .

Contents of the invention

The invention provides an internal injection emergency cooling control structure and method of a battery pack, and relates to the field of battery thermal management. Through the induction of the hot melt in the hot melt nozzle to the overheated battery module, a signal is transmitted and the emergency cooling is started. The high-pressure refrigerant encapsulates the flame retardant and sprays it through the nozzle towards the overheated battery module. On the one hand, the refrigerant vaporizes and absorbs heat, and on the other hand, the flame retardant suppresses combustion, and then the high-pressure airflow in the package is discharged through the pressure relief device. The invention effectively inhibits the overheated battery module from developing in the direction of thermal runaway and greatly improves the safety of electric vehicles.

In order to achieve the above objects, the present invention provides the following technical solutions: Firstly, embodiments of the present invention provide an internal injection emergency cooling control structure of a battery pack. The structure includes an automobile control unit (1), an automobile refrigeration system (2), Controllable valve (3), hot melt nozzle (4), flame retardant storage tank (5), power battery module (6), refrigerant main flow pipe (7), first pressure relief exhaust valve (8) , battery pack shell (9), second pressure relief exhaust valve (10); the refrigerant main flow pipe (7) is connected to the automobile refrigeration system (2); the controllable valve (3) is installed on the refrigerant The main flow pipe (7) is located close to the automobile refrigeration system (2); the power battery module (6) is placed in the internal space of the battery pack shell (9) and evenly distributed; the flame retardant storage tank (5 ), and the hot melt nozzles (4) are arranged in sequence on the branches branched from the refrigerant main flow pipe (7); the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) are in The battery pack shell (9) is arranged symmetrically in the horizontal direction and is located at the far end of the hot melt nozzle (4). The two pressure relief exhaust valves are of electromagnetic adsorption type and can be closed and opened for pressure relief by turning on and off power; The automobile control unit (1) receives signals from the hot melt nozzle (4) and transmits control signals to the controllable valve (3), the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10); The controllable valve (3) controls the refrigerant main flow pipe (7) to introduce refrigerant from the automobile refrigeration system (2); the hot melt nozzle (4) controls the branches of the refrigerant main flow pipe (7). It opens and closes and functions as a nozzle, and also has the function of obtaining and sending signals.

In a preferred embodiment of the present invention, the hot melt nozzle (4) includes a hot melt (4-1), a capacitive reactance sensing device (4-2), a nozzle (4-3), and a hot melt nozzle (4-1). -1) It has the characteristics of melting at a given higher temperature and will not be broken by the refrigerant when hot melt does not occur. The refrigerant and resistance between the hot melt (4-1) and the refrigerant main flow pipe (7) The flame retardant in the fuel storage tank (5) is compatible and does not support combustion; the capacitive reactance sensing device (4-2) can measure the change in capacitive reactance of the hot melt (4-1) and send it to the vehicle control unit (1 ) transmits signals; the nozzle (4-3) can evenly spray the working fluid passing through it onto the surface facing the power battery module (6).

In a preferred embodiment of the present invention, the flame retardant storage tank (5) is a structure that stores flame retardant internally. The inlet and outlet are sealed with a film. The flame retardant inside the tank (5) has the function of blocking oxygen and inhibiting combustion activation molecules. (group) and is compatible with the refrigerant in the refrigerant main flow pipe (7) and the hot melt (4-1) in the hot melt nozzle (4), the flame retardant storage tank (5) is It remains closed under normal working conditions. When the controllable valve (3) is opened, the film at the inlet and outlet of the flame retardant storage tank (5) is broken by the refrigerant and the flame retardant is released into its corresponding branch.

In a preferred embodiment of the present invention, the refrigerant fluid pressure provided by the automobile refrigeration system (2) is relatively high, which can remove the flame retardant in the flame retardant storage tank (5) and the residual in the hot melt branch. The hot melt (4-1) is entrained and flows, and can form a uniform spray through the nozzle (4-3), covering the surface of the battery module.

In a second aspect, embodiments of the present invention provide a method for controlling internal injection emergency cooling of a battery pack. The method includes:

When the power battery module (6) in the internal space of the battery pack casing (9) overheats, the temperature of the module itself rises rapidly, and the corresponding hot melt (4-1) senses the high temperature and melts, and the corresponding pipe The branch is no longer blocked by the hot melt (4-1), and the refrigerant can be introduced from the refrigerant main flow pipe (7);

When the hot melt (4-1) melts, the capacitive reactance sensing device (4-2) collects the capacitive reactance change signal and calculates the melting rate of the hot melt (4-1), which is immediately transmitted to the car control unit (1), after processing, the automobile control unit (1) transmits the control signal to the controllable valve (3), and adjusts the controllable valve (3) according to the hot melt rate v and the number n of hot melts in the hot melt (4-1) 3) The opening S, the specific methods and related descriptions are as follows:

a. When the thermal melt rate v>v ₂ , n modules are rapidly overheated and the degree of danger is extremely high. The controllable valve is fully opened. At this time, the final result of the battery's thermal runaway cannot be changed, but the development can be prolonged. When the time comes for combustion and explosion, give personnel time to escape;

b. When the hot melt rate v ₁ ≤ v ≤ _{v 2} , n modules have experienced high-speed overheating at this time, and the degree of danger is high. In order to quickly cool down the flame retardant and take into account the continuous effects of the refrigerant and the flame retardant. , the controllable valve opening is adjusted to n*S ₂ ;

c. When the hot melt rate v < v ₁ , n modules are generally overheated at this time, and the degree of danger is low. In order to ensure the continuous effect of the refrigerant and flame retardant, a small flow and long-term cooling method is adopted. , the controllable valve opening is adjusted to n*S ₁ ;

After judgment, cooling and flame retardancy, the vaporized airflow in the internal space of the battery pack shell (9) is discharged through the pressure relief exhaust valve.

In the preferred embodiment of the present invention, the relevant description of the continuous effect of the refrigerant and the flame retardant:

a. The refrigerant can continuously and fully vaporize and absorb heat. Excessive flow rate will cause the refrigerant to be quickly exhausted and prone to incomplete vaporization and cold protection, which weakens the subsequent vaporization and heat absorption effect of the refrigerant;

b. The flame retardant can continuously and fully cover the surface of the battery module. When the refrigerant with an excessive flow rate passes through the branch quickly, the flame retardant is not completely released from the flame retardant storage tank (5), and the refrigerant only A small part of the flame retardant is entrained and then sprayed onto the surface of the battery module through the nozzle (4-3), which weakens the utilization rate of the flame retardant.

In a preferred embodiment of the present invention, when the vaporized airflow in the internal space of the battery pack shell (9) is discharged, the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) switch rules and related descriptions as follows:

a. If only one module overheats, open the pressure relief exhaust valve far away from the module. Opening the pressure relief exhaust valve far away can allow the vaporized air to flow through most of the space in the battery pack, which can effectively Prevent battery modules in normal working conditions from overheating;

b. When multiple modules are overheated, open the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) at the same time. When multiple battery modules are overheated, the air pressure in the package is extremely high, and it is necessary to Open all pressure relief and exhaust valves to quickly relieve pressure to prevent the battery pack from bursting.

The emergency cooling structure proposed by the present invention can effectively suppress the occurrence of thermal runaway when the battery overheats. It uses the basic principle of vaporization and heat absorption of refrigerant to absorb the heat generated by the overheated battery module, and uses flame retardants to block oxygen and inhibit The basic principle of combustion activation molecules (groups) inhibits the occurrence of combustion, controls the continuous deterioration of overheated batteries from multiple angles, and comprehensively and reliably ensures the safety of cars and personnel.

The control strategy proposed by the present invention effectively takes into account the transient effects and continuous effects of cooling and flame retardancy by taking different levels of emergency measures for batteries with different overheating degrees. Under the premise of a certain total amount of refrigerant, the emergency response can be maximized. As a result, after completing the cooling and flame retardancy, the two pressure relief exhaust valves are used to cleverly organize the flow of vaporized airflow, which plays a preventive cooling role for the battery module that has not been overheated and prevents the battery pack from being damaged by high voltage.

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and therefore do not It should be regarded as a limitation of the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a structural principle diagram of the present invention;

Figure 2 is a control flow chart of the present invention;

Description of labels in Figure 1:

1-Car control unit 2-Car refrigeration system 3-Controllable valve

4-Hot melt nozzle 5-Flame retardant storage tank 6-Power battery module

7-Refrigerant main flow pipe 8-First pressure relief exhaust valve 9-Battery pack shell

10-Second pressure relief exhaust valve

Explanation of symbols in Figure 2:

N-The total number of battery modules in the battery pack

n-The number of battery modules that have overheated in the battery pack

A-The volume of a single branch hot melt

v-The maximum value of the hot melt rate of each branch

S-controllable valve opening (0%-100%, 0% corresponds to closed, 100% corresponds to fully open)

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. The following detailed description of the embodiments of the invention provided in the appended drawings is not intended to limit the scope of the claimed invention, but rather to represent selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without any creative work fall within the scope of protection of the present invention.

As shown in Figure 1., the injection emergency cooling control structure in the battery pack consists of an automobile control unit (1), an automobile refrigeration system (2), a controllable valve (3), a hot melt nozzle (4), and a flame retardant storage tank. (5), power battery module (6), refrigerant main flow pipe (7), first pressure relief exhaust valve (8), battery pack shell (9), and second pressure relief exhaust valve (10) , Figure 1. The ellipses in the logo represent repeated structures, including the refrigerant main flow pipe (7), the flame retardant storage tank (5), the hot melt nozzle (4), the power battery module (6), and the battery pack shell (9) Partially. The automobile refrigeration system (2) provides refrigerant for the entire control structure, which is introduced from the refrigerant main flow pipe (7). The refrigerant main flow pipe (7) branches out branches, and flame retardant storage tanks are installed on each branch in turn. (5) Hot melt nozzle (4), the nozzle (4-3) is horizontally positioned above the power battery module (6) so that the spray can evenly cover the surface of the module, and the power battery module (6) is evenly distributed Inside the battery pack shell (9), the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) are geometrically symmetrically arranged on the battery pack shell (9) in the horizontal direction and located on the hot melt nozzle (4 ) at the far end. When the first battery module on the left side of the internal space of the battery pack casing (9) overheats, the corresponding hot melt (4-1) melts, and the capacitive reactance sensing device (4-2) receives the hot melt (4 The capacitive reactance change signal of -1) is converted into a hot melt rate and then transmitted to the automobile control unit (1) together with the number of change signals. After processing, the automobile control unit (1) transmits the control signal to the controllable valve (3) and the vent. The pressure exhaust valve, controllable valve (3), and pressure relief exhaust valve are quickly adjusted according to the rules. The refrigerant enters the refrigerant main flow pipe (7) and the branch where the hot melt phenomenon occurs as the controllable valve (3) is adjusted. On the way, the inlet and outlet films of the flame retardant storage tank (5) are broken by the refrigerant entering the corresponding branch, and the flame retardant is released into the corresponding branch. Since the refrigerant pressure of the automobile refrigeration system (2) is relatively high, High, it can overcome layer-by-layer resistance, mix the compatible refrigerant, flame retardant, and hot melt (4-1) and spray them evenly from the nozzle (4-3) to the overheated battery module, but no heat will occur. The molten hot melt (4-1) will not be broken by the refrigerant, thereby preventing spraying. The refrigerant in the mixture vaporizes and absorbs heat and changes to a gaseous state. The flame retardant covers the surface of the overheated battery module to isolate oxygen and To suppress the effect of activated molecules (groups), the air pressure in the bag rises sharply due to the vaporization of the refrigerant. According to the rules, the power supply to the first pressure relief exhaust valve (8) is cut off, the electromagnetic adsorption disappears, and the exhaust valve acts on the pressure difference. The bottom is flushed open, and the vaporized refrigerant immediately forms a vaporized air flow and quickly rushes to the first pressure relief exhaust valve (8), passing through other battery modules in the middle, which plays a role in preventing cooling and ensuring the normal operation of the battery module. Without turning into an overheated state, as the refrigerant and the flame retardant in the branch where the hot melt phenomenon occurs continue to repeat the above process until exhausted, the overheated battery module will no longer develop into thermal runaway, ensuring the safety of vehicles and personnel.

As shown in Figure 2., at a certain moment when an electric vehicle is driving, the hot melt (4-1) inside a battery pack with N battery modules undergoes a hot melt phenomenon, and a single branch hot melt The volume of (4-1) is A. Emergency measures are immediately initiated, and an alarm notification is sent to the vehicle occupants to escape quickly. At the same time, the capacitive reactance sensing device (4-2) obtains the capacitive reactance change signal of the hot melt (4-1). After being converted into a heat melt rate, it is transmitted to the vehicle control unit (1) together with the number of change signals n (representing that n battery modules have overheated and caused n branches to have heat melt phenomena), and the maximum heat melt rate v is obtained. , the automobile control unit (1) outputs a control signal to the controllable valve (3) and the pressure relief exhaust valve. The adjustment rules of the controllable valve (3) are as follows:

a. When v>20%*A/s, that is, when the hot melt (4-1) is hot melted at a rate exceeding 20% of its maximum volume per second, the opening of the controllable valve (3) is adjusted to S =1/N*100%*n;

b. When 10%*A/s≤v≤20%*A/s, that is, when the hot melt (4-1) is hot-melted at a rate of 10%-20% of its maximum volume per second, the controllable valve The opening adjustment of (3) is S=1/N*60%*n;

c. When v<10%*A/s, that is, when the hot melt (4-1) is hot melted at a rate lower than 10% of its maximum volume per second, the opening of the controllable valve (3) is adjusted to S=1/N*30%*n.

After the vehicle control unit (1) processes the input signal and delays for 2 seconds, the pressure relief exhaust valve begins to adjust. The specific rules are as follows:

a. When n=1, determine the location of the overheated battery module and cut off the power supply to the pressure relief exhaust valve far away from it;

b. When n≠1, cut off the power supply to all pressure relief exhaust valves.

Claims (5)

1. A battery pack internal injection emergency cooling control structure, characterized by including an automobile control unit (1), an automobile refrigeration system (2), a controllable valve (3), a hot melt nozzle (4), and a flame retardant storage Tank (5), power battery module (6), refrigerant manifold (7), first pressure relief exhaust valve (8), battery pack shell (9), second pressure relief exhaust valve (10) ; The refrigerant main flow pipe (7) is connected to the automobile refrigeration system (2); The controllable valve (3) is installed on the refrigerant main flow pipe (7) close to the automobile refrigeration system (2); The power battery module (6) is placed in the internal space of the battery pack shell (9) and evenly distributed; The flame retardant storage tank (5) and hot melt nozzle (4) are arranged in sequence on the branches branched from the refrigerant main flow pipe (7); The first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) are symmetrically arranged in the horizontal direction of the battery pack shell (9) and located at the far end of the hot melt nozzle (4). The exhaust valve is an electromagnetic adsorption type, which can be closed and opened to achieve pressure relief by turning on and off power; The automobile control unit (1) receives signals from the hot melt nozzle (4) and transmits control signals to the controllable valve (3), the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) ); The controllable valve (3) controls the refrigerant main flow pipe (7) to introduce refrigerant from the automobile refrigeration system (2); The hot melt nozzle (4) controls the opening and closing of the branches of the refrigerant main flow pipe (7) and functions as a nozzle, and also has the function of obtaining and sending signals; The hot melt nozzle (4) includes a hot melt (4-1), a capacitive reactance induction device (4-2), and a nozzle (4-3). The hot melt (4-1) has the ability to operate at a given higher temperature. It has the characteristics of melting and will not be broken by the refrigerant when hot melt does not occur. The hot melt (4-1) and the refrigerant in the refrigerant main flow pipe (7) and the resistance in the flame retardant storage tank (5) The fuel is compatible and does not support combustion; the capacitive reactance sensing device (4-2) can measure the capacitive reactance change of the hot melt (4-1) and transmit a signal to the automobile control unit (1); the nozzle (4-3) The working fluid passing through it can be evenly sprayed onto the surface facing the power battery module (6); The flame retardant storage tank (5) is a structure that stores flame retardant internally. The inlet and outlet are sealed with a film. The flame retardant inside has the function of blocking oxygen and inhibiting the production of combustion activated molecules and activated groups, and is in contact with the flame retardant storage tank (5). The refrigerant in the refrigerant main flow pipe (7) is compatible with the hot melt (4-1) in the hot melt nozzle (4). The flame retardant storage tank (5) remains sealed under normal working conditions. When the controllable valve (3) is opened, the membrane at the inlet and outlet of the flame retardant storage tank (5) is broken by the refrigerant and the flame retardant is released into its corresponding branch. 2. The internal injection emergency cooling control structure of the battery pack according to claim 1, characterized in that the refrigerant fluid pressure provided by the automobile refrigeration system (2) is relatively high, and the flame retardant storage tank (5) can be The flame retardant and the hot melt (4-1) remaining in the hot melt branch flow together, and can form a uniform spray through the nozzle (4-3), covering the surface of the battery module. 3. A battery pack internal injection emergency cooling control method, characterized in that it is applied to the battery pack internal injection emergency cooling control structure according to any one of claims 1-2, and the method includes: When the power battery module (6) in the internal space of the battery pack casing (9) overheats, the temperature of the module itself rises rapidly, and the corresponding hot melt (4-1) senses the high temperature and melts, and the corresponding pipe The branch is no longer blocked by the hot melt (4-1), and the refrigerant can be introduced from the refrigerant main flow pipe (7); When the hot melt (4-1) melts, the capacitive reactance sensing device (4-2) collects the capacitive reactance change signal and calculates the melting rate of the hot melt (4-1), which is immediately transmitted to the car control unit (1), after processing, the automobile control unit (1) transmits the control signal to the controllable valve (3) and the pressure relief exhaust valve, and the heat melt occurs according to the maximum hot melt rate v of each branch and the hot melt (4-1) The number n of hot melt adjusts the opening S of the controllable valve (3). The overheating degree of the module is divided into three stages according to the hot melt rate, where v ₁ =10%*A/s, v ₂ =20%*A /s, S ₁ =1/N*30%, S ₂ =1/N*60%, A is the volume of a single branch hot melt, N is the total number of battery modules in the battery pack, specific methods and related Described as follows: a. When the hot melt rate v>v ₂ , that is, when the hot melt (4-1) is hot melted at a rate exceeding 20% of its maximum volume per second, n modules are rapidly overheated to a dangerous degree. Extremely high, the controllable valve is fully open. At this time, the final result of the battery's thermal runaway cannot be changed, but it can prolong the development time to combustion and explosion, giving personnel time to escape; b. When the hot melt rate v ₁ ≤ v ≤ _{v 2} , that is, when the hot melt (4-1) is hot melted at a rate of 10%-20% of its maximum volume per second, n modules will High-speed overheating is highly dangerous. In order to quickly cool down and flame retardant while taking into account the continuous effects of refrigerant and flame retardant, the controllable valve opening is adjusted to n*S ₂ ; c. When the hot melt rate v < v ₁ , that is, when the hot melt (4-1) is hot melted at a rate lower than 10% of its maximum volume per second, general overheating of n modules occurs at this time, which is dangerous. The degree is low. In order to ensure the continuous effect of the refrigerant and flame retardant, a small flow and long-term cooling method is adopted, and the controllable valve opening is adjusted to n*S ₁ ; after judgment and cooling and flame retardant, the battery The vaporized air flow in the inner space of the package shell (9) is discharged through the pressure relief exhaust valve. 4. The method according to claim 3, characterized in that the relevant description of the continuous effect of the refrigerant and the flame retardant: a. The refrigerant can continuously and fully vaporize and absorb heat. Excessive flow rate will cause the refrigerant to be quickly exhausted and prone to incomplete vaporization and cold protection, which weakens the subsequent vaporization and heat absorption effect of the refrigerant; b. The flame retardant can continuously and fully cover the surface of the battery module. When the refrigerant with an excessive flow rate quickly passes through the branch, the flame retardant is not completely released from the flame retardant storage tank (5), and the refrigerant only A small part of the flame retardant is entrained and then sprayed onto the surface of the battery module through the nozzle (4-3), which weakens the utilization rate of the flame retardant. 5. The method according to claim 3, characterized in that when the vaporized air flow in the internal space of the battery pack shell (9) is discharged, the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) The switching rules and related descriptions are as follows: a. If only one module overheats, open the pressure relief exhaust valve far away from the module. Opening the pressure relief exhaust valve far away can allow the vaporized air flow to flow through most of the space in the battery pack, which can effectively Prevent battery modules in normal working conditions from overheating; b. When multiple modules are overheated, open the first pressure relief exhaust valve (8) and the second pressure relief exhaust valve (10) at the same time. When multiple battery modules are overheated, the air pressure in the package is extremely high, and it is necessary to Open all pressure relief and exhaust valves to quickly relieve pressure to prevent the battery pack from bursting.